However Improbable
by toinkeroo
Summary: John is Sherlock's imaginary friend growing up. One day, he says the words you're never meant to say, not unless you're ready to say goodbye. Growing up is a cold, lonely journey after that. Until years later, when he accidentally says the words that bring him back.
1. Chapter 1: Prologue

So I finally decided to give this a try. I hope you allow me a few disclaimers as I start:

Firstly, it is my first time to write a story for this fandom. I hope you will forgive any mistakes or OOC moments.  
Secondly, I am not a native of the British Isles, and publish my work unbeta-ed. So I am pretty sure there will be some language/tone lapses around. Please do bring them to my attention so I can correct. :)  
Lastly (not a disclaimer), I am still learning about all this, so I really welcome feedback and advice. :)

** xxx**

I hope you enjoy the story! :) Will do my best to post updates quickly.

* * *

"John. Pass me the scissors."

Sherlock sighs. John is in one of his moods again. Hadn't he already blown off his steam the past two days? Really, sometimes John could be so _tedious_.

"The scissors, John." He huffs. "It's in the upper drawer of the second shelf." After half a minute he adds, "Please?" in what is, hopefully, a more polite tone.

"John, honestly," he says, "This is getting ridiculous. Weren't you the one who wanted to work on this stupid model of the solar system anyway? And whatever happened to, '_We're growing up, you need to stop acting so childish_'? Who's acting childish now, John?"

Sherlock looks up from his work station, the various odds and ends he and John had gathered from all over (The neighbor's shed, Mr. Cleaver's thrift store, and filched here and there from unsuspecting victims. Nothing too valuable, nothing that would be missed-that was John's only condition.) and peers at the shadow behind the dresser, where he knows John will emerge, looking resigned and contrite. He always feels guilty after hiding from Sherlock for more than a day.

He waits two more minutes, before allowing himself to feel a slight note of panic. "John?"

** xxx**

_i._

_Bargaining_, his brain perfunctorily supplies. From some Psychology book, perhaps, or one of mummy's so-called "self help."

"I'll even let you place the rings on Saturn," he says, daring to speak up in the hallway outside Father's study. John loved running along this corridor-no big vases or figurines for Sherlock to knock over and get scolded for-Father was a very practical man.

"I'll drink my milk on time tonight," he says in front of the refrigerator, wincing at his pathetic offer. Need to be more persuasive, he thinks. "I'll stop experimenting on the dog." The cook is staring at him strangely. "For a week," he quickly adds. "A month?" he asks again, staring at the sterile whiteness.

_ii._

_Anger_, his subconscious recalls and provides.

"Are you trying to 'teach me a lesson' again, John? Is this your funny little way of making yourself feel important?" If his voice breaks a little, Sherlock either doesn't notice or doesn't care. He keeps shouting at the ceiling. "Bravo, John! I always knew you were the more mature one."

"_Best friend_." He spits the words out in the most painful way he knows how. Except-painful to whom? "Where's my so-called best friend when I need him?"

_iii._

_Bargaining, _again. Really, Sherlock thinks, he did not expect his own reactions to be so _pathetic _and _predictable _that a simple psychology textbook had been able to explain it to him. But even as a part of him wanted to prove it wrong-he was special, John said, not like the others, in a _good _way-he couldn't help himself as he continued to lash out at the wall, the ceiling, the shadows behind the dressers, the spaces under the shelves.

"I take it back, alright? Are you happy now?" He curls his fingers into fists so hard he can feel his nails digging into his palms. Nerve endings responding to stimuli, reminding his brain that he could still feel. He thought he would always have John to remind him of that. _How hateful_. "Whatever it was that I said, or I did, _I take it back, do you hear me? I take it back!"_

_iv._

_Denial_, he thinks afterwards.

_v._

_Acceptance_, Mycroft insists, once he deduces what happened. He is short on patience that day, and cannot spare any for his wayward brother and his caprices. Besides, he just turned eight a week ago, he should know better.

"Really though, Sherlock, it was about time." And that, perhaps, is what hurts most of all.

** xxx**

Mummy insisted that Mycroft come along with her to meet with Sherlock's doctor. Mummy insisted on a lot of things.

A few years ago, she took him aside and insisted that Mycroft never question Sherlock about John. However, she also insisted that he introduce Sherlock to his other friends from school, _to help him diversify, _she'd said.

Mummy insisted, as they left the doctor's office, that he never call his little brother a sociopath to his face. And to never bring up John Watson again.

** xxx**

Sherlock never ends up turning in his science project that term. Saturn and all its rings, the sun, the moon and stars, are sent out with the rubbish in the morning. Cook finds that all the milk cartons have been emptied in the sink. A few more of mummy's vases and china get removed from the hallway and placed in storage for safe-keeping.

A few short weeks after his eighth birthday, Sherlock deletes the solar system.


	2. Chapter 2: My Best Friend

_In which we discover the origins of John, Sherlock's best friend_.

Mycroft wonders if he will ever truly stop worrying about his little brother. Perhaps he had just grown accustomed, over the years, to watching a little too closely and getting involved a little too much in his brother's life.

Sherlock, for his part, spared no expense in letting his older brother know how his concern was neither sought nor appreciated. It is a taxing job, being a sibling, but every time Mycroft even considers lashing out at his brother for his irresponsibility and penchant for self-destruction-he keeps going back to that day back when they were children: Sherlock staring at his brother in absolute betrayal, and watching him walk away, so much smaller and defeated than any eight year old should ever be.

Who was this brother of his, this child who had to grow up too fast, this child who never got to grow up at all?

* * *

The first time Mycroft meets John, Sherlock serves him tea and a slice of tiramisu.

"Cook doesn't have any cheesecake even though John and I _reminded _her _several times _to buy the ingredients last week-I even did some research and listed them down for her!-so we had to make do with whatever was left from Mummy's brunch. You understand that this entire affair is not _my_ idea, it's John's because he has wanted to meet you for a while now because you've been out for school for _so boringly long _and he thinks you would make a very good thief when we play our joolery hides game because you're always so quiet that I never hear your when you're coming."

Mycroft smiles as his little brother catches his breath. "Do you mean jewelry heist, Sherlock?"

"Oh," Sherlock's brow furrows as he tries out the word. "Joolery hites."

"Heist."

"Heist," the younger boy repeats impatiently. "Anyway so will you join us? John told me we had to play nice and entertain first like Mummy and Father do because you're our guest today and then bribe you with cake." Sherlock looks at the chair on the other side of the table and frowns. "John says I shouldn't have told you it was a bribe. He says you won't accept it if we do. Why not? You'll take the bribe, right, My?"

Mycroft laughs and ruffles his brother's hair. He takes the proffered slice of cake and takes a bite. "Of course, brother dear. Now," he leans conspiratorially. "Tell me about this heist you've been planning."

* * *

Mummy had, of course, briefed him about 'John' a few days after he had arrived back from school. She had explained, in great detail, that this situation was perfectly normal for children of Sherlock's age who were very curious, active and imaginative.

"There's nothing to worry about, Mycroft. This is a completely normal, healthy thing for your little brother. He is four years old, and it is natural for him to explore and learn about the world and social interactions in this way," she kept repeating. She went on at length about all the things the family doctor had said, the explanations he had given. Their mother had always been one to worry a great deal about all sorts of things, and Mycroft listened mostly because he realized she needed this reassurance more than he did.

He was not worried at all, actually. He had already met John a few days back and was pleased to find that Sherlock's friend was, in fact, a good influence on him, imaginary or not.

Sherlock's eyes had gone bright and he perked up when Mycroft asked him if he had made any friends while his older brother was away.

"John is my best friend," Sherlock said, chest puffed out and back straight. "He says I am special and there is no one else like me-but special in, you know, a _good_ way, not the _bad _special, like monsters and Uncle Christopher."

The little boy got silent for a minute and seemed to think on what he just said. He clutched his big brother's jacket sleeve. "Am I _good_ special, Mycroft?"

"Yes, you are, Sherlock," Mycroft hugged his brother close. "You really are."

"He wants to meet you," Sherlock said, very seriously. "We have a fore-position for you."

"Proposition," Mycroft gently corrected. "And yes, I would love to meet him and hear it."

Sherlock looked up at his brother and smiled.

* * *

"Would you help me with this problem?" Sherlock asks one afternoon, bringing his chair closer to his brother's desk and clambering on. "John isn't very good with maths, his forpe is really sports and exploring and animals, but he says that there's nothing wrong with asking for help when we think we need it."

"That's very good of John to say."

Sherlock scoffs. "It's tiresome, but useful sometimes. John is always telling me about rules and how to do things and what not to say, but when I tell older people what he said they just laugh at me and let me go." He shrugs. "So I guess it's alright."

"Do they?" Mycroft peers at his brother, hunched up on his piece of paper.

"They say I'm _adorable_," Sherlock makes a face. "And I should learn to be a _little_ _gentleman_ like John." He shakes his head and gets back to writing. "Too many rules. _Boring._"

"Does John always tell you off about things? Make you follow the rules?"

"He tries. I don't always follow what he says because it gets so tedious and he keeps saying the same things over and over anyway. '_Don't run too fast, you may hit the vases.' 'Little boys should always drink milk before bedtime.' 'It's not good to get mud on the carpet.'_ UGH. He even told me off for saying the word 'shite' the other day! It wasn't my fault that Maggie was telling Cook about it!" Mycroft smiles as he watches his brother's petulant exclamations and wild arm gestures. "Sometimes he can be so _unreasonable_."

"But you let him go on."

Sherlock looks at Mycroft and raises his brow. "Honestly Mycroft, you're supposed to be smart, right? _He's my best friend_," Sherlock insisted, as if that was all the explanation his older brother deserved. Perhaps, Mycroft thought, that was indeed all the explanation he really needed.

* * *

He hated himself, even years after, for leaving his brother alone the time John left. His brushing off of Sherlock in his brother's time of need had marked the first in a long line of betrayals.

"Really, Sherlock, it was about time."

Sherlock, voice worn out from screaming and sobbing all night, eyes puffy and wet, stared wordlessly at his older brother. His little eight-year old body vibrated as he tried to control his sobs, shaking his head vigorously. His own body betrayed him though, breath hitching softly at first, until it escalated into full-blown sobs.

He had nothing to say to his older brother that day. He had nothing to say to his older brother for a very long time.

* * *

_Sometimes I wonder why I've not been knighted yet. GL_

Mycroft raises his brow at the unexpected text. His assistant had not forwarded any concerns or issues based on the latest surveillance, which means whatever trouble Sherlock had gotten into now, it was, at least, confined within the walls of DI Lestrade's office. At least, one hopes.

_When I had provided my number to you for emergency purposes regarding my brother, inspector, I was expecting a bit more detail and actionability in the wording of your updates. MH_

_Can't a bloke have a segue? Anyway, this is merely to inform you that your brother is being temporarily detained for a minor misconduct. Should be out by tomorrow. No need to post bail. GL_

_As long as you can ensure he does not get to any harm, I leave him to your hands, inspector. MH_

_Not my hands you should be worried about, I think? He seems a bit agitated, little too excitable and frantic, to be honest. Checked him for substances though, just to be sure, and he's clean. Do you know what's going on? GL_

_Has he mentioned anything of import? MH_

_Not much. Just something about an old friend coming back and needing to meet him back in his flat. GL_

Mycroft had to stop and think back, tapping his fingers gently on the table. Had there really been nothing noteworthy in the recent reports? Sherlock's only other acquaintance that could possibly visit was Victor, from university, but he had it on reliable resources that the man was out for a trip with his family in Scotland for a month, having just left the week before. That could not be him, then. Then, who?

_Did he give a name? MH_

_Yes, actually, now that you mention it. Someone named John? Anyone you know? This better not be one of his old dealers. GL_


	3. Chapter 3: Some Nights

**Chapter 3: Some Nights**

Some nights are the worst. Others are important. Some nights are both.

* * *

**Notes:** So. I'm not sure what happened. Here I thought, I would run merrily along and be able to update this with a moderately decent offering once every week? every other week maybe?

And then. And. Then. Real life came and kicked me in the butt.

Anyway, to make it up, I'm putting up two chapters this time-although to be honest this first one is rather short, and not much happens (maybe?). I did feel it was necessary to the story and couldn't fit it elsewhere in the next chapter. Not much angst this time around. (That's a good thing?)

Hope you still enjoy! :) Please do let me know what you think-I'd love to hear your thoughts, especially if there's any way to improve!

* * *

Some nights are the worst. Quiet nights when there are no crime scenes to disturb, no evidence to steal, no cases, nothing-nothing! _God,_ how_inhuman_. Not even the distraction offered by the dull, mundane minutiae of all the insipid, ordinary people milling about as they do in the day. Nothing but the buzzing, empty quiet of the night. How he _hated _it.

The chair and couch are too close to the bed. Move it? Ugh, cannot be bothered; too tedious and do not want to move. Chair needs to be moved out of sight of the bed. Rather, bed needs to be moved out of sight of the chair. Better yet, close eyes, do not bother looking at anything at all. Most especially not that cold, empty bed.

After 20 minutes, or thirty or an hour, he gets up. Perhaps enough time has passed to check on the progress of the cultures he had been cultivating. White bread, wheat or rye? Perfectly valid variables.

He nearly stumbles as he hits the edge of a three-foot stack of books, causing the skull to fall, jaw landing squarely on the floor.

_Ah._ The unexpected and surprisingly welcome gift from the best of his homeless network. Angie certainly has taste. He picks it up and strokes the smooth white enamel with delicate fingers. A fine specimen indeed.

"What stories do you have to tell?" he murmurs.

The ring of his mobile interrupts his quiet inquiry.

"Lestrade. Hmmm, yes, I had noticed." He grunts, deftly spinning the skull with one hand. "It would delight you to hear that I am, actually, quite capable of, quote, dealing with my downtime. I don't need your nannying, especially as I find your inquiry and subsequent report to a certain government official absolutely redundant. You know he monitors the flat. Yes, of course I know, what do you think of me?"

It is quiet on the other end of the line and Sherlock's eyes narrow and light up, almost at the same instant. He stalks to the fireplace and posts the skull squarely on the corner of the mantel.

"This isn't a courtesy call, is it? You _have _something. _Tell me_-no, actually, don't bother; just give me the address. Hmm, yes. I'll be there in twenty minutes."

Sherlock ends the call, turning around to locate his discarded jacket.

"Well, that was a satisfactory turn-around, wasn't it?" He turns back to the skull, suddenly thoughtful. "What should I call you? Good partners must have acceptable names."

* * *

He should have known that night would be significant.

* * *

**Notes:** I told you didn't I? Time to move on to the next chapter! :) xx


	4. Chapter 4: All that Matters

**Chapter 4: All that Matters**

_If this was a ruse, a clever ruse by his own defunct hardware, it was a cruel and capricious one and Sherlock thought, savagely, even sociopaths must have some limit. What does that even mean? Nevermind. Not important. Not. Important. To open the door, this instant, would be important._

* * *

Thirty-two minutes after the morning light had started to filter in the stingy window, Sherlock hears steady footfalls making their way to his cell. He does not move an inch from his current position, back flat and legs straight along the sparse cot, eyes closed and palms joined as in prayer, fingers touching his lips.

When he hears the locks open and the man shuffling somewhere at his head, he offers the smallest of acknowledgements, eyes narrowly open as he murmurs, "I told you it was the mail boy, but did you listen?"

Lestrade huffs and shakes his head, "Alright, alright, you were right. That's what you wanted to hear, right?"

"Wrong! I would much rather you release me immediately."

"Yes, well, regardless of how you feel about the matter, I still need you to get back and sign some paperwork."

Sherlock snorts and straightens up, feet on the floor, hands adjusting the lapel of his jacket. "I've told you, I have things that I need to get back to. Matters requiring my immediate attention."

"Is this about that John fellow?" Lestrade asked, frowning. "Because Mycroft just did a check-and there's no one else at your flat, or the surrounding area for that matter."

The younger man's eyes narrowed into the thinnest slits, "You had no business talking to my brother about-those things."

"Woah, is that hesitation I hear? Think you're losing your sting, mate." Lestrade moved to settle beside an unnervingly silent Sherlock. "So who is he anyway? Why're you so wired to see him again?"

"This is a matter you don't need to worry yourself about-and before you say anything , it's _not_ anything to do with drugs. I've been clean for months, I have no intention of resorting to that again." For a moment Sherlock looked at him almost pleadingly. "Believe me."

A heavy sigh. "I believe you, Sherlock."

Sherlock stands and waits just inside the door with uncharacteristic politeness, although Lestrade could feel his nervous energy from the balls of his feet.

Lestrade turned and grinned at the him, "You must introduce me someday."

After wasting two more useless hours at the station, Sherlock walked out of the Met and went back to his flat. No use delaying the inevitable. John was back. And he had never been this frightened in his life.

* * *

_Theories, theories, _all he had were theories and _none_ of them made sense. John, in his flat, waiting. How did he even know John would be waiting?-he had better wait, after leaving Sherlock all those years. Sentiment. John, in his flat, back in his life, his own improbability, offered to him. Visible, present, in full size and shape and color.

He walked, dazed, along the street. Walked up, mind blissfully empty of all expect the fact that in nine, eight, seven more steps he would open the door and see John again. John, waiting, as he made Sherlock wait all these years.

Goodness, how long had he stopped making promises to random metaphysical beings arbitrarily assigned homes up in the ether? How many constellations had he deleted and re-entered and re-deleted, entire galaxies and supernovas burnt out from one little boy's stubborn decision to stop believing?

If this was a ruse, a clever ruse by his own defunct hardware, it was a cruel and capricious one and Sherlock thought, _savagely_, even sociopaths must have _some limit_. What does that even mean? Nevermind. Not important. Not. Important. To open the door, this instant, would be important.

What would he even say? Where does one begin?

* * *

The morning of John's return, he had been having an overwhelmingly difficult time relaying simple instructions to the new pathologist at St. Barts. Molly Hoopers's usefulness was surpassed only by her sheer idiocy.

He was pacing across the cramped floor space of the flat, narrowly avoiding stacks of books along the way. He clutched and pulled at his curls in frustration.

"Listen-stop talking, stop blubbering-_just listen. _I need you to make an incision right underneath the left socket. Yes, yes, about 2 centimetres, and then I need you to pour hydrogen peroxide in the open wound. What? Do you see the reaction? Describe it to me? No, no, it has to be _right now_ or the results won't be right, keep your hand steady and… _WHAT_? What did you _do?_ Well don't just stand there, record it! Take a video or-what? Good god, woman, couldn't you at least have gotten a phone with a decent camera? Stop talking! Stop talking and start recording! I'm on my way now."

Punching angrily on the keys of his blackberry, he stalked to the doorway, grabbing his scarf and coat. _The sheer incompetence of some people!_

"You shouldn't talk to her like that. She _is_ helping you, you know."

"She is being especially difficult and incompe-" He froze. His head swung so fast as he looked around, trying to trace the voice. _That voice_. There was no way he should have recognized it now, not with the decades that passed, physiological changes that should have gotten in the way-not that there was real physiology involved of course, but the mind was a wonderful thing, curator and creator, and-goodness that voice. He would recognize it at any time, at any place.

"Still haven't learned to take care of yourself, Cap'n?"

He made a noise quite close to a choke. Damn his self control. (Or lack of one.) "I have been certified by a few choice institutions as complete shite at it, to be honest."

Sherlock turned, slowly, almost as if he were afraid to look. There, standing by the fireplace, hands clasped at his back and looking at him with a level gaze, was John.

Years of reflexive observation and deduction warred with a deeper, stronger instinct-to RUN. Fight or flight-and at the back of his mind Sherlock chastised himself for succumbing to such a primitive urge, but there it was-he stood rooted on the spot, mind going on overdrive with the sheer enormity of the data. Quality, he'd always said, not quantity of the data made for the most important deductions.

* * *

Later on as he would sit by himself in the cell, he could hardly recount any of the minute, physical details of that moment. Only that John looked at him as he had always looked at him. John looked at him as if Sherlock was his best friend, as if after all this years nothing had changed, and as if that was all the mattered.

* * *

It is their first case after Lestrade releases Sherlock from his custody and into the arms of his long, lost friend, 'John.' Lestrade had yet to be granted the privilege of meeting him. An attempted inquiry through Mycroft proved unsuccessful, and even without the forbiddingly calm look and pursed lips directed at him, the DI was quick to give it up as new cases had accumulated and claimed almost all his time.

It had gotten to the point where he was overwhelmed enough to call upon the self-proclaimed consulting detective, who had been uncharacteristically holed up in his flat for the past week. Big. Mistake. Big mistake.

Lestrade clutches his cellphone tightly, imagining a pale, slender neck in its stead as he vacillates between typing out his message or simply saying fuck-it-all and throwing the damn thing at a certain annoying, curly-haired idiot. Seriously, the nerve of this man.

Is it not enough that he is being allowed access to crime scenes, to cases, to puzzles that are somehow able to distract him from his less noble vices? Does he not realize how much the DI is putting on the line for this-this-this _brat's_ caprices? Must he make a fool of Lestrade, of his team, of the entire police force and its institution with his… toy?

He snaps. "Is this all a game to you, Sherlock?"

Sherlock whips to him, interrupted mid-deduction, the thing balanced quiet casually on his left palm. "Pardon?"

"This isn't one of your playground games, Sherlock, no matter how easily this comes to you. You have no _right_ to make a scene here."

"Exactly _who _is making a scene?" Lestrade gets a good serving of sardonic brow. "I am here at _your request_, solving _your case _for you. _You _are the one causing a scene right now."

"Sherlock…" _Breathe. Breathe._ It does not help that he barely had five hours of sleep in three days. It really doesn't. "Can you explain to me _why,_exactly, you have decided to bring that skull along to one of my crime scenes?"

Sherlock looks at him, blinking, confused. He glances at the skull, then somewhere behind him. A look almost like embarassment creeps on his face, but he is quick to rearrange it.

The consulting detective sniffs, "Helps me think."

* * *

**Notes:** Not much has happened yet, I know, I know! Give John some time to settle in, okay? We will get there soon, I promise.

Let me know what you think? :) I love hearing from you guys! xxx

I owe you guys a bunch for making you wait, so here's a sneak preview of the next bits:

1) An implosion.

2) An explosion.

3) People move out. Again.

Yes? No? Haha. Thanks for reading! :)


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